Alloyed quantum dots (QDs) show great potential for photoluminescence (PL) applications. However, the oxidative decay of QDs during photoexcitation has been a major hurdle to the application of QDs. Blocking water-oxygen erosion by coating oxides on the surface of QDs is a common technique. Even though, this approach often leads to alterations in the optical properties of QDs and reduced compatibility with polymers. In this paper, hindered phenol was utilized to treat QDs to form QD/Hindered phenol complexes. Using the reduction of phenolic hydroxyl group in the hindered phenol, the hindered phenol was used as an exhausted substance to protect QDs from oxidation . After 450 h of aging, the obtained QD/Hindered phenol complex kept the photoluminescence quantum yield (PLQY) at 48 %. The luminance of the QD diffusion plate prepared by the QD/Hindered phenol complexes maintained above 98 % of the initial value after aging 1032 h. The introduction of phosphite ester further improved the photostability of QD/Hindered phenol complex under blue-light excitation. This technique promotes the application of QDs in polymers and offers a new reference for improving the stability of QDs under photoexcitation.
A simple and effective method based on magnetic solid-phase extraction combined with high performance liquid chromatography was used for the determination of hindered phenolic antioxidants in plastic packaging injections. The extraction and clean-up via Fe3O4@CTAB magnetic adsorbent dispersion in injections was followed by magnetic isolation and desorption of the analytes using acetonitrile. The cationic surfactant cetyltrimethylammonium bromide (CTAB) coated on the surface of Fe3O4 nanoparticles adsorbent was synthesized. The main parameters affecting the adsorption recoveries were evaluated and optimized, including the amounts of surfactant and adsorbent, pH, ionic strength, desorption conditions, and sample volume. Under the optimum conditions, the method was successfully applied to the determination of hindered phenolic antioxidants in plastic packaging injections. Low limits of detection (LODs) of 0.14 and 0.15 µg mL−1 and limits of quantification (LOQs) of 0.45 and 0.50 µg mL−1 were achieved. The mean recoveries were in the range from 85.0% to 93.5% at 5, 10, and 20 µg mL−1 spiked levels, and the relative standard deviations (RSDs) were in the range from 1.16% to 2.81%.
危险品化学品经营许可证（带存储）